A marine research ecologist at Dalhousie University says a new study is further proof we need to change the way we manage fisheries around the world.

"If you fish these stocks the exact same way you're fishing them now and you keep that up, then indeed we will face in 30 years or so a world where according to this study almost 90 percent of stocks are depleted," Boris Worm told CBC's Mainstreet.

The study, published last week in the Proceedings of the National Academy of Sciences, shows while there are improvements in some areas of the world, the average state of fish stocks is poor and declining. Worm wrote a commentary on the study that will be published next month. 

Of close to 5,000 fisheries assessed, only one third remained at a biomass target that supports maximum productivity. Two thirds have slipped below that threshold. 

1/3 of stocks poised to recover

Even more concerning, Worm says, is the finding that only one third of stocks are currently fished at a level that would allow for recovery. He says one way to reverse the trend is to listen to scientists and reduce overfishing. 

Boris Worm

Dalhousie professor Boris Worm says one way to reverse the trend of declining fish stocks is to listen to scientists and reduce overfishing. (Bob Murphy/CBC)

The other, faster approach is convincing fishermen that with the right conservation steps, they can make more money.

"If there are more fish in the water you have to use less fuel, fewer boats, less time on the water to catch those fish," Worm said.

"You get the same income for less cost."

Calling for end of fuel subsidies

Worm says governments also have to stop propping up unprofitable and unsustainable fisheries by offering subsidies for fuel and the construction of new boats that exist in many regions.

"I've seen in the Mediterranean for example, boats coming back with lots of fishermen on them, lots of employment, big new boats but very few fish that were landed," he said. 

Worm says the report is also significant because of who is behind it.

"It comes from a group of American scientists who have been quite outspokenly optimistic about the future of fisheries and this study confirms that optimism may be OK in some regions like our own but not so much elsewhere."

Though he wasn't involved in writing the study, Worm was invited to give commentary on it. Those comments will be published in the print version of the publication.

with files from Mainstreet